1. Field of the Invention
The present invention relates to an image processing device and image processing method.
2. Description of Related Art
Image processing devices, such as color copiers, create color images by controlling a scanner to read an image and by controlling an ink-jet printer to print the read image.
Normally, the scanner employs a line sensor such as a CCD line sensor or a CIS (Contact Image Sensor) line sensor. The line sensor converts the read image into analog electrical signals. The analog electrical signals are converted into digital signals, and print data is produced based on the digital signals. The ink jet printer performs printing based on the print data to reproduce the original image.
Especially in a color copier that performs full-color image reproduction, the line sensor includes a R-line sensor unit for red, a G-line sensor unit for green, and a B-line sensor unit for blue. When the line sensor reads a color image on a document line by line, each line sensor unit reads the color image line by line and detects a corresponding color component of the image. Thus, each line sensor unit produces a successive groups of corresponding color-component image data for successive lines read by the subject line sensor unit. After being digitized, three groups of red, green, and blue image data indicative of the same line image are converted together into a group of print data for reproducing the color of the subject line image.
It is noted that when the ink-jet printer contains cyan, magenta, and yellow inks, the group of print data is made up from print data for cyan, magenta, and yellow. When the ink-jet printer contains cyan, magenta, yellow, and black ink, the group of print data is made up from print data for cyan, magenta, yellow, and black. Print data for each ink is compared with a threshold and binarized into dot-forming data or non-dot forming data according to the comparison results. The ink-jet printer prints each line image by selectively ejecting ink of various colors based on the corresponding print data group, thereby selectively superimposing the various inks. The read image is reproduced in this way.